This CELL CORE has continuously served this Program Project for 25 years and has all necessary infrastructure, equipment, space and personnel. Dr. Henson originated the human blood cell isolation procedures that are still in use for the provision of leukocytes. Dr. Bratton has overseen the blood cell isolation and regulatory management of this resource for many years now. Dr. Leslie and her laboratory have provided consistent, continuous macrophage isolation and cell culture. Human alveolar macrophages provided by our collaborator Dr. Robert Mason (see letter) to the CELL CORE will be cultured and distributed to the Projects. Sources of the provided cells are four: 1) isolated human blood cells, 2) human alveolar macrophages, 3) resident macrophages from the lungs and peritonea and bone marrow cells for macrophage derivation from knockout and wild type mice, and 4) cultured cell lines. Brief methods for cell isolation and culture are described and a reference list detailing procedures to be utilized is included. The description of dedicated space, equipment and necessary resources is outlined in the Resources and Environment section. The Budget Justification for the CELL CORE reflects services and resources to be utilized in common for two or more Projects.